In the packaging of snack foods the snack food is delivered to a weighing machine from where batches of the food are delivered to a packaging machine that forms the bags. Traditionally the bags have been of a single size. However more recently smaller bags have been formed and are known as a “single serve” bag. The smaller bags are contained in a larger bag for distribution. Accordingly bags of a number of different sizes are now produced.
Slip conveyors are used to deliver the snack food to the weighing machine, with the conveyor including longitudinally extending trays that are longitudinally vibrated (reciprocated) to transfer material along the conveyor. The longitudinal oscillation is rapid in one direction and slow in the other. The material is transported in the slow direction. Conveyors, including slip conveyors are described in U.S. Pat. No. 7,228,957 and U.S. patent application Ser. No. 11/108,052 (lodged on 14 Apr. 2005) and Ser. No. 11/263,762 (lodged on 31 Oct. 2205).
In the packaging industry, particularly the industry relating to the packaging of snack foods, product is delivered to a group of weighing machines, each of the weighing machines then communicates with an associated packaging machine such as the packaging machine described in U.S. Pat. No. 4,663,917. Conveyors, such as slip conveyors deliver the product to the weighing machines.
The above discussed arrangement for producing bags has the disadvantage that the packaging machines are set up to form only one particular size of bag. When a bag of a different size is to be produced, the machine needs to be altered, in particular the former needs to be replaced. This requires the packaging machines and associated conveyors to be shut down. Accordingly a further disadvantage is that production is interrupted.